1. Technical Field
The present invention relates to a liquid jet head and a liquid jet apparatus that jet and record liquid droplets on a recording medium.
2. Related Art
In recent years, liquid jet heads in an ink jet system have been used, which eject ink droplets on a recording paper or the like to record characters and figures, or eject a liquid material on a surface of an element substrate to form a functional thin film. This system introduces a liquid such as an ink or a liquid material from a liquid tank to a channel through a supply tube, applies a pressure to the liquid filled in the channel, and ejects the liquid through a nozzle that communicates with the channel, as liquid droplets. In ejecting the liquid droplets, this system moves the liquid jet head and/or the recording medium to record the characters and figures or to form a functional thin film or a three-dimensional structure having a predetermined shape.
FIG. 6 is a schematic cross-sectional view of jet channels 113 of a liquid jet apparatus described in JP 2001-88295 A. The liquid jet apparatus is a side shoot-type liquid jet apparatus in which an actuator substrate 100 made of a piezoelectric material, a nozzle plate 140, and a manifold member 132 are laminated. The actuator substrate 100 is made of a piezoelectric material, and the manifold member 132 is made of a synthetic resin. A plurality of the jet channels 113 is formed in the actuator substrate 100. The jet channels 113 have a long and narrow groove shape and penetrate in a thickness direction of the actuator substrate 100. Adjacent jet channels 113 are partitioned by a side wall 117. A drive electrode 119 is formed on an entire wall surface of the side wall 117. A pattern of an electric supply line (not illustrated) is provided on an upper end surface of the actuator substrate 100, and one end of the electric supply line is electrically connected to the drive electrode 119 on the wall surface and the other end is connected to a control circuit. The manifold member 132 includes a manifold flow path (not illustrated) that supplies a liquid to the jet channels 113, and a plurality of ink flow paths 134 that branches from the manifold flow path. The ink flow paths 134 of the manifold member 132 are bonded on the upper end surface of the actuator substrate 100 through an adhesive 138, respectively corresponding to the jet channels 113. The nozzle plate 140 includes nozzles that communicate with the jet channels 113, and is bonded on a lower end surface of the actuator substrate 100.
The side wall 117 of the actuator substrate 100 is uniformly polarized (P) in the thickness direction of the actuator substrate 100. A voltage is applied to drive electrodes 119c and 119d of a jet channel 113a to be driven. When drive electrodes 119b and 119e of two jet channels 113 adjacent to the jet channel 113a are grounded, both side walls 117a and 117d of the jet channel 113a to be driven are subjected to thickness slip deformation, and are deformed in a direction into which the volume of the jet channel 113a is increased. A side wall 137 of the manifold member 132 is deformed following the deformation of the side wall 117 of the jet channel 113, and is deformed in a direction into which the volume of the ink flow paths 134 is increased. Therefore, the liquid is drawn from the manifold flow path (not illustrated) to the jet channels 113. Next, the voltage applied to the drive electrodes 119c and 119d of the jet channel 113a is returned to (0) V, and the both side walls 117a and 117d of the jet channel 113a are returned to the shape before the deformation. At this time, a relatively large pressure is applied to the liquid, and the liquid droplets are jetted through a nozzle 118a. 
JP 2003-110159 A describes an adhesive structure in which a thick piezoelectric ceramic plate and a thin piezoelectric ceramic plate adhere together through an adhesion layer. Polarization processing is applied to the thick piezoelectric ceramic plate and the thin piezoelectric ceramic plate in a vertical direction to a substrate surface, the polarization directions are caused to be opposite directions, and the two piezoelectric ceramic plates adhere together through the adhesive, so that the adhesive structure (laminated piezoelectric body substrate) is obtained. At that time, the roughness of a surface at a side opposite to an adhesion surface of the thin piezoelectric ceramic plate is made to 1 μm or less in arithmetic mean roughness (Ra), so that a bend or a waviness of the adhesive structure is decreased. Then, cutting is performed from a side of the thin piezoelectric ceramic plate into a depth in the middle of the thick piezoelectric ceramic plate, and a plurality of grooves, which is partitioned by side walls, is formed in parallel in an upper surface of the adhesive structure. An electrode for driving the side walls is formed on the entire wall surfaces of the side walls and bottom surfaces of the grooves using a vapor deposition method or a sputtering method. A top plate including a liquid supply path adheres to a top face of the adhesive structure. A nozzle plate including nozzles adheres to an end surface of the adhesive structure. The liquid jet head is configured, accordingly. When a drive signal is applied to the electrode installed on both wall surfaces of the side walls, the side walls are deformed, a pressure is applied to the liquid filled in the grooves, and liquid droplets are jet through the nozzles that communicate with the grooves.
In JP 2009-119788 A, JP 2009-178959 A, JP 2009-202455 A, JP 2012-111130 A, JP 2012-187863 A, and JP 2002-505972 W, liquid jet heads having a similar structure to the grooves and the side walls described in JP 2003-110159 A are described. That is, a laminated piezoelectric body substrate is formed, in which two piezoelectric body substrates polarized in mutually opposite directions adhere together, and a plurality of grooves partitioned by side walls is formed in parallel in the laminated piezoelectric body substrate. A drive electrode is formed on the entire wall surfaces of the side walls that configure the grooves. When a drive signal is applied to the drive electrode, the side walls are deformed, a pressure is applied to a liquid filled in the grooves, and liquid droplets are jet through nozzles that communicate with the grooves.
JP 2003-507213 W describes a jet channel, in which a plurality of grooves partitioned by side walls is formed in parallel in a surface of a piezoelectric body substrate, which is polarized in one direction, and a drive electrode is installed on upper half portions of wall surfaces of the side walls. When a drive signal is applied to the drive electrode, the upper half portions of the side walls is subjected to thickness slip deformation, and a pressure is applied to a liquid filled in the grooves, and liquid droplets are jet through nozzles that communicate with the grooves.
In the liquid jet apparatus described in JP 2001-88295 A, the adjacent jet channels 113 are partitioned by the side wall 117 to which the polarization processing is uniformly applied. The drive electrode 119 is formed on the entire wall surface of the side wall 117. In the liquid jet heads described in JP 2003-110159 A, JP 2009-119788 A, JP 2009-178959 A, JP 2009-202455 A, JP 2012-111130 A, JP 2012-187863 A, and JP 2002-505972 W, the piezoelectric materials having different polarization directions are laminated on the side walls that configure the jet channels, and the drive electrode is formed on the entire wall surfaces of the side walls. As a method of forming the electrode on the entire wall surfaces of the side walls, a plating method can be employed. However, the electrode formed by the plating method is deposited on the bottom surfaces of the grooves, in addition to the wall surfaces of the side walls. To alternately arrange ejection channels and non-ejection channels, and perform one-cycle driving of ejecting the liquid droplets through all of the ejection channels at one time, it is necessary to electrically divide the electrodes on the two wall surfaces. Therefore, manufacturing process steps become complicated and the number of man-hour is increased.
Meanwhile, in the jet channel described in JP 2003-507213 W, the electrode is formed on the upper half portions of the wall surfaces of the side walls. If a conductive material such as a metal material is deposited by an oblique vapor deposition method, electrically separated electrodes can be easily formed on two wall surfaces that face each other across the groove, without depositing the conductive material on the bottom surface of the groove. Therefore, an electrode separation step of electrically separating the electrodes deposited on the two wall surfaces is not necessary. However, with a demand of high densification of recording with the jet channel, the groove width of the grooves that configure the jet channel is narrowed. The oblique vapor deposition method requires a longer time to deposit the conductive material in the depth direction of the wall surface as the groove width becomes narrower, and productivity is reduced.